Method, transmission unit, system and computer program for wireless communication between a camera and at least one remote flash device

Abstract

The present invention generally relates to the field of communication between electronic devices used for photography. In particular, the invention relates to a method, transmission unit, system and computer program for wireless communication between a camera and at least one remote flash device, such as photoflash units and related equipment. More in particular, the invention provides a way of controlling a plurality of flash devices from an intermediate radio transmission unit mountable on the camera, and utilized a delay a sequence flash control sequence so as to synchronize the function of the camera and the remote flash devices during image acquisition. Further the invention provides a way of controlling in the photoflash units settings for the main flash, wherein the setting are the last settings determined by the camera when the intermediate radio transmission unit was in a TTL-mode.

What is claimed is: 
     
       1. A method for adjusting a power relation between a plurality of different remote flash devices using through-the-lens (TTL) flash control and an intermediate radio transmission unit for wireless transmission of radio signals to the remote flash devices and for bi-directionally exchanging signals with a camera via a physical connection between the intermediate radio transmission unit and the camera, the method comprising the steps of:
 receiving information or setting by the respective remote flash devices the amount of power that the remote flash devices should use for their respective preflashes; 
 receiving by the respective remote flash devices a preflash activation signal received from the camera via the intermediate radio transmission unit; 
 emitting at the same point in time from the respective remote flash devices preflashes with a power relation according to the received information or setting received by the remote flash devices, wherein the power relation is adjusted between the plurality of different remote flash devices using through-the-lens (TTL) flash control; 
 receiving by the remote flash devices one common amplification based on the preflashses to be applied during subsequent main flashes from all of the different remote flash devices, said one common amplification from the camera via the intermediate radio transmission unit; 
 receiving by the remote flash devices a main flash activation signal from the camera via the intermediate radio transmission unit; 
 applying in the remote flash devices the one common amplification to the power for the respective preflashes; and 
 emitting at the same point in time from the respective remote flash devices main flashes with a power relation corresponding to the power relation for the preflashes. 
 
     
     
       2. The method according to  claim 1 , wherein the information or setting received by the respective remote flash devices about the amount of power that the remote flash devices should use for their respective preflash are set in the intermediate radio transmission unit. 
     
     
       3. The method according to  claim 1 , wherein the information or setting received by the respective remote flash devices about the amount of power that the remote flash devices should use for their respective preflash are transmitted in the preflash activation signal. 
     
     
       4. The method according to  claim 1 , wherein the information or setting received by the respective remote flash devices about the amount of power that the remote flash devices should use for their respective preflash are transmitted before the preflash activation signal. 
     
     
       5. The method according to  claim 1 , wherein the setting for the remote flash devices to apply during the main flash is an indication if the power from the remote flash devices should be increased or decreased, and with how much the power should be increased or decreased. 
     
     
       6. The method according to  claim 1 , wherein a preflash image analysis is made to determine settings relating to the amount of light energy required for exposure of an image acquisition in present lighting conditions. 
     
     
       7. The method according to  claim 1 , wherein a remote flash device uses an in-built flash radio receiver unit for receiving signals from the intermediate radio transmission unit. 
     
     
       8. A non-transitory computer readable medium having a program stored thereon for executing a computer to perform the method in accordance with  claim 1 . 
     
     
       9. The method according to  claim 1 , wherein the amount of power that each of the remote flash devices should use for their respective preflashes is different. 
     
     
       10. The method according to  claim 1 , wherein the information or setting in the respective remote flash devices of the amount of power that the remote flash devices should use for their respective preflashes varies. 
     
     
       11. A method performed in an intermediate radio transmission unit for adjusting a power relation between a plurality of different remote flash devices using through-the-lens (TTL) flash control, the method comprising the steps of:
 transmitting information to the respective remote flash devices corresponding to different amounts of power for their respective preflashes; 
 receiving from a camera a preflash activation signal; 
 transmitting the preflash activation signal to the respective remote flash devices preflashes for emission with a power relation according to the information transmitted to the respective remote flash devices, wherein the power relation is adjusted between the plurality of different remote flash devices at least in part using through-the-lens (TTL) flash control; 
 transmitting one common amplification to be applied during subsequent main flashes to all of the different remote flash devices, said one common amplification being received from the camera; and 
 transmitting to the remote flash devices a main flash activation signal received from the camera. 
 
     
     
       12. The method according to  claim 11 , wherein the information transmitted to the respective remote flash devices corresponding to the different amounts of power of their respective preflashes varies. 
     
     
       13. The method according to  claim 11  wherein the intermediate radio transmission unit is mountable in a hot shoe connector of the camera. 
     
     
       14. The method according to  claim 11 , wherein a confirmation signal is transmitted to the camera indicating that a remote flash device is momentarily unavailable, the indication being realized by setting a clock signal of the intermediate radio transmission unit in its low state. 
     
     
       15. The method according to  claim 11 , wherein an availability signal is transmitted to the camera indicating that a remote flash device is available, the indication being realized by setting a clock signal of the intermediate radio transmission unit in its high state. 
     
     
       16. The method according to  claim 11 , wherein the intermediate radio transmission unit is adaptable to operational properties of the camera to which it is connected. 
     
     
       17. The method according to  claim 16 , wherein operational properties of the intermediate radio transmission unit relate to physical properties and/or a communication interface of the camera to which the unit is connected. 
     
     
       18. The method according to  claim 11 , wherein the information transmitted to the remote flash devices for the respective preflashes is previously determined by the camera in a through-the-lens mode of the intermediate radio transmission unit. 
     
     
       19. The method according to  claim 18 , wherein the steps in  claim 1  are performed with the intermediate radio transmission unit in a manual mode after the step in  claim 3  is performed with the intermediate radio transmission unit in the through the lens mode. 
     
     
       20. Intermediate radio transmission unit for wireless transmission of radio signals to several remote flash devices and for bi-directionally exchanging signals with a camera via a physical connection between the intermediate radio transmission unit and the camera, the intermediate radio transmission unit being adapted to control settings of several remote flash devices and to synchronize its function to image acquisition of the camera in accordance with the method of  claim 11 . 
     
     
       21. A camera system for controlling settings of at least one remote flash device and for synchronizing its function to image acquisition of a camera, the camera system including the intermediate radio transmission unit in accordance with  claim 20 , and being adapted to control settings of the remote flash device and to synchronize its function to image acquisition of the camera in accordance with the method. 
     
     
       22. A method for through-the-lens, TTL, control of a plurality of different remote flash devices, said method comprising the steps of:
 receiving by the different remote flash devices respective inputs indicating amounts of power that the different remote flash devices should use for preflashes, wherein the plurality of different remote flash devices are controlled at least in part via through-the-lens, TTL, control; 
 emitting at the same point in time from the different remote flash devices preflashes with different powers according to the received respective inputs; and 
 receiving by the different remote flash devices one common amplification relating to the amount of light energy required from the different remote flash devices for exposure of an image acquisition in present preflash lighting conditions based on the preflashes emitted with the amounts of power as indicated by the respective inputs. 
 
     
     
       23. The method according to  claim 22 , further comprising the steps of:
 applying in the remote flash devices the one common amplification to the power for the respective preflashes; and 
 emitting at the same point in time from the respective remote flash devices main flashes with a power relation corresponding to the power relation for the preflashes. 
 
     
     
       24. A method performed in an intermediate radio transmission unit for through-the-lens, TTL, control of a plurality of different remote flash devices, said method comprising the steps of:
 transmitting to the different remote flash devices respective inputs indicating amounts of power that the different remote flash devices should use for the preflashes, wherein the plurality of different remote flash devices are controlled at least in part via through-the-lens, TTL, control; 
 transmitting to the remote flash devices an activation signal for emitting at the same point in time from the different remote flash devices preflashes with different powers according to the respective inputs; and 
 transmitting to the different remote flash devices one common amplification relating to the amount of light energy required from the different remote flash devices for exposure of an image acquisition in present preflash lighting conditions based on the preflashes emitted with the amounts of power as indicated by the respective inputs. 
 
     
     
       25. The method according to  claim 24 , further comprising a step of:
 transmitting to the remote flash devices a main flash activation signal for emitting at the same point in time from the respective remote flash devices mainflashes with the one common amplification.